Many devices, such as car navigation devices, audio devices, and air conditioners (air conditioning devices) which are mounted in vehicles and there has been a problem for the driver, namely the increased amount of gaze movement made to manipulate buttons, check control panel displays, and perform other tasks that are necessary when these devices are operated.
To mitigate this problem, use of gesture manipulation input has been considered.
For example, a device for gesture manipulation input has been proposed (in patent reference 1, for example) that extracts an image of a hand from an image taken by an imaging means, determines the intended manipulation from the shape and movement of the hand, and notifies the user by displaying a menu item selected on the basis of the determined manipulation.
Patent reference 1 also teaches providing a visible light camera and an infrared camera as imaging means, using the visible light camera in bright surroundings, and using the infrared camera in dark surroundings.
When the infrared camera is used, in consideration of the susceptibility of infrared cameras to outdoor light effects, a method of obtaining the image of the hand by periodically switching the infrared light on and off at short intervals and calculating a difference image has been proposed (in patent reference 2, for example).